Field
The disclosed concept pertains generally to the monitoring of waveforms in electrical systems and, more particularly, to a data decimation technique and system for facilitating the transmission and display of waveforms, such as transient voltage spike/surge waveforms, in an electrical system.
Background Information
In the context of electrical systems, spikes, also known as surges, are fast, short duration electrical transients in voltage (voltage spikes), current (current spikes), or transferred energy (energy spikes) in an electrical circuit. Spikes can be caused by any of number of events, such as, without limitation, lightning strikes, power outages, tripped circuit breakers, short circuits, power transitions in other large equipment on the same power line, malfunctions caused by the power company, and electromagnetic pulses (EMPs).
When a spike occurs, it is important to analyze the spike in order to determine the cause and/or severity thereof. Failure to do so may lead to infrastructure damage, safety hazards, and downtime, among other issues. This is usually done by capturing a waveform representing the spike (e.g., a voltage waveform) using a metering device and analyzing that waveform at, for example, a remote location on a client device such as a PC, laptop computer, tablet or smartphone.
However, many metering devices capture the transient waveforms at a high sampling rate, resulting in a large number of data points. For example, it is not uncommon for a metering device to capture and create waveforms that constitute more than 100,000 data points in a 20 millisecond (ms) cycle time (6 MHz). In addition, the metering device may be able to operate at multiple cycle time, such as the cycle time just described and 1141 Hz, 16,666 samples per cycle, 120 ms duration cycle time. Such large amounts of data can cause traffic and/or performance problems when attempts are made to transport the data from the metering location (using a separate server or a server embedded in the metering device) over one or more networks (such as the Internet and/or a mobile data transmission network) to the target client device and display the data at the client device. For example, consider a metering device that captures and creates waveform data having 134,600 points in a 20 millisecond cycles time. If a client device having a pixel resolution of only 1920 were to try to display these point as is (i.e. without reducing them), the graph would look very dense and would therefore be difficult to read. A number of additional traffic and/or performance and usability issues may also be present, such as, without limitation, communication problems such as software breakdown, excessive cost in the case of mobile clients, and performance issues at the client device, such as excessive time required to plot data and/or to zoom in/out and pan.